Metal container and process for its manufacture



May 7, 1957 v R. MbRAND' 2,791,349

METAL CONTAINER AND PROCESSWFOR ms MANUFACTURE w Filed June 24. 1954 I5Sheets-Sheet 1 g INVE-N TOR ROBERT MORA ND 7 May 7, 1957 R. MORAND2,791,349

' METAL. CONTAINER AND PROCESS FOR ITS MANUFACTURE I 3 Sheets-Sheet 2Filed Jung 24. 1954 "pl-1'11 I INVEINIOR ROBERT MORAND May 7, 1957'METAL CONTAINER AND PROCESS FOR ITS MANUFACTURE Filed June 241954 R.MORAND 5'Sheets-Sheet 5 INVENTOR ROBERT MORAND BY VJ/#141,411

United States Patent lVlETAL CONTAINER AND PROCESS FOR ITS MANUFACTURERobert Morand, Beaurepaire, France, assignor to Exlam Societe Anonyme,Tangier, a corporation of the International Zone of Tangier ApplicationJune 24, B54, Serial No. 438,971 Claims priority, applicationSwitzerland June 29, 1953 1 Claim. (Cl. 220-54) This invention relatesto a seamless metal container having a top which is hermeticallyattached to the shell of the container and which is removable by meansof a novel arrangement.

Containers having the same purpose as that of the present inventionhave, for instance, been described in U. S. Patents Nos. 1,615,930 and1,764,883. In these containers, a blank stamped from a sheet of iron isformed into a cylindrical shell after the sheet had had a double foldformed therein to provide a lip around the inside of the container whichwill form the upper edge of the container after it has been opened. Thelongitudinal edges of the blank are then connected together to form aseam. The difficulty comes in connecting the edges of the blank at thepoint where the threefold thickness of the double fold occurs. Thepatents recommend tapering oil the thickness of the double fold byappropriately shaping the blank in order that the ends of the doublefold may overlap in the region of the seam without forming an additionalthickness. At the same time, there is formed in the vicinity of the partof the container which will be removed to permit removal of the cover alateral extension of the blank which, when the blank is formed into acylindrical shell, will form a tab lying against the outer surface ofthe cylindrical shell to form a tab to which a slotted key can be fittedto tear out a portion of the container to open it.

While the necessity of using a seamed container has obvious drawbacks,including the difliculty of forming a perfect seal and the operations offorming the blank into a cylindrical shell, the manner of forming thetab is convenient. However, the material of the sheet in that area intowhich the tab projects is substantially all waste, inasmuch as there isno corresponding point on the other end of the blank into which this tabfits. Thus the blanks cannot be stamped out in an interlocking pattern.

It is an object of the present invention to provide a container whichhas the advantages of the seamless container relating to the ease ofproduction, ease of hermtic sealing, and at the same time has a means ofremoving the cover which is similar to the use of the tab on thecontainer of the prior art but which uses no extra material and causesno waste of material. In addition the container of the present inventionis provided with a construction by which the cover, after it is onceremoved and the hermetic seal is broken, can be replaced on thecontainer to close it.

The disadvantages of the prior art containers are eliminated in the caseof the container according to the invention. This is achieved accordingto the invention by forming the shell from a light-metal tube which iscontinuous over the whole of its circumference and is preferably drawn.In contrast with the known containers which have been mentioned above,the container according to the invention has no longitudinal seamcrossing the circumferential folding and is made of light-metal,

this material allowing the circular folding to be formed on the tubularshell blank.

The absence of the longitudinal seam furthermore oifers the additionaladvantage of enabling the bottom end and/0r top to be fitted more easilyto the tubular shell, and of making the problem of obtaining a tightjoint between the shell and the bottom end respectively the top easierto solve.

The process for the manufacture of the container and a preferredembodiment thereof, given by way of example, are described in thefollowing with reference to the drawing. In the various figures shownthe same parts are always designated by the same reference.

In the drawing:

Figs. 1, 2, 3 and 4 illustrate four different successive phases of themanufacturing process of the container according to the invention;

Figs. 5, 6, 7 and 8 are sectional views, corresponding to Figs. 1-4,showing the last four phases of manufacture, the finished containerbeing shown in Fig. 8;

Fig. 9 is an enlarged partial sectional view taken on line 9-9 of Fig.10; and

Fig. 10 is a partial side view of the parts shown in section in Fig. 9.

For the manufacture of the container use is made of a blank which may,for instance, have the shape shown in Fig. 1. It is supposed that thecup shaped blank 1 has been formed by drawing a piece of alloyedaluminium sheet, so that it has a cylindrical part 1 and a bottom part2. The free edge 3 of the blank has already been cut to the correctdimension.

This blank is now provided, as may be seen in Fig. 2, in theneighbourhood of the free edge 3 with a channel 4, preferably by meansof a dishing operation carried out on the rotating blank with rolls.After this, the blank being kept rotating, the channel is given anunsymmetrical shape as shown in Fig. 3, by means of appropriatelyform-ed tools. The profile 5 of the channel is now composed of a shortsteeply inclined flank 6 and a longer flank 7 which is only slightlyinclined in relation to the wall of the blank 1. Two parallelcircumferential score lines 8 and 9 are now cut on the inside of theblank above the channel 5 (Fig. 4). A strip 11 of sheet metal liesbetween these score lines and, as will be described later on, will serveas tear strip. All these phases of the process are carried out on thetrimming machine.

After the above described steps have been carried out, the channel isnarrowed to a fold and then, as shown in Figs. 5 and 6, laid in anupward direction against the inner side of the container wall. In orderto do this, the two flanks 6 and 7 are brought together by means of apress so that an upwardly inclined fold 22 with a folding line 23 isformed. After the fold has been bent over (Fig. 6) the folding line 23is situated slightly above the score line 9, and this has the advantagethat after the tear strip 11 has been removed, the container has nocutting edge which would prevent it from being subsequently used again.In addition a slight outwardly projecting bulge is formed below thefolding by means of a pressing, dishing or similar operation.

After the bottom part 2 has been cut oif, the upper and lower edges 25and 26 are formed in small flanges (Fig. 7). Finally the bottom partproper 27 is fitted and its edge is rolled and pressed together with theflange 26 in the usual way. After the container has been filled, the top29 is also fitted and secured in the same manner. When the container isfinished, the score line 8 is situated at the same level as the loweredge 30 of the seam securing the top. The purpose of the inwardlyprojecting bulge 28 may be seen below.

As shown in Figs. 9 and 10, a portion having a thickness less than thethickness of the shell 1, e. g. a score line 35, defining a tab 36 isprovided on the outside of the Container, one end 38 of this score linebeing situated at the same level as the inner score line 8, whereas theother end 39 lies in the neighbourhood ofthescore line 9. At the end ofthe tongue 36, i. e. in the middle portion of the tear strip 11, thescore line 35 is broadened to form a region 37 also of reduced thicknessand able to be pierced, which may for instance be pierced by the end ofa container opening key 40 ground to form a screw-driver edge 41. Thetongue-shaped score line 36 and the weakened region 37 are all that canbe seen from the outside of the container. After the tool has beenthrust through at the point 37, the tongue 36 can be slightly raised andits end introduced into the slit 42 of the container opening key, afterwhich the tongue 36 and the strip 11 can be rolled up with ease.

In order that the key may' be able to pierce the portion of reducedthickness, the top 29 has a depressed central portion extending into theinterior of the shell. This portion has a diameter less than the innerdiameter of the shell 1 so that there is defined between the depressedportion and the portion of the shell 1 above the top edge of the doublefold at 23 an annular space. The diameter of the depressed centralportion is substantially equal to the inner diameter of the double fold,so that when the stop 11 has been removed, the depressed central portionwill fit tightly into theinside of the doublefold.

This arrangement is particularly advantageous because the container isabsolutely hermetieally sealed and is very simple. The score lines 8 and9 could of course be formed on the outside of the container, and theends 38 and 39 of the score line 35 would then run directly into thescore lines 8 and 9.

In other embodiments ofthe container the bottom part could be in onepiece with the shell. In addition it would also be possible, instead ofdrawing the blank, to obtain it for instance by extrusion.

What I claim is:

A filled metal container comprising a seamless cylindrical shellhermetically closed at its lower end and a top member hermeticallysealed to the upper end of said shell, said shell having a continuouscircumferential double fold formed from the shell itself around theshell near the upper end thereof and lying against the inner wall of theshell, said shell having two spaced score lines around the interior ofthe shell between said fold and the upper end, one of said score lineslying in the portionof said shell against which said fold liesimmediately below the upper edge of said fold and the other fold linelying between the upper edge of said fold and the upper end, said shellfurther having a portion of a thickness less than the thickness of saidshell I defining the outline of a tab between said score lines,

and said top'havinga' depressed central portion extending into theinterior or said shell and having a diameter less than the innerdiameter of said shell and substantially equal to the inner diameter'ofsaid double fold,

said depressed portion and the shell above said double fold defining anannular space therebetween, whereby a' tool may be inserted into saidspace through said portion of reduced thickness to lift the tab andremove the part of said shell between said score lines.

References Cited in the file of this patent

